Rapid Quantification of Soyasaponins I and βg in Italian Lentils by High-Performance Liquid Chromatography (HPLC)–Tandem Mass Spectrometry (MS/MS)

Abstract

In this work, an innovative and fast analytical method for the quantification of soyasaponins I and βg in lentils has been developed. Samples were extracted using 70 % aqueous ethanol at room temperature and then injected into a high-performance liquid chromatography–tandem mass spectrometry system. The correlation coefficients of calibration curves of the analyzed compounds were ≥0.9997. The recoveries obtained by spiking the lentil samples with a standard mixture of soyasaponins I and βg at 50 and 100 mg l−1 were in the range of 96–101 and 98–103 %, respectively. The validated method was applied to the analysis of 30 lentil samples from central Italy. Soyasaponins I and βg were present in these lentils in concentrations that ranged from 54 to 226 mg kg−1 and from 436 to 1,272 mg kg−1, respectively. Our data indicated that lentils cultivated in fields at intermediate altitudes (1,142–1,387 m) showed the highest levels of soyasaponins, a finding confirmed by principal component analysis.